Hedonism
Hedonism gets a bad rap. People assume hedonism is the nihilistic pursuit of pleasure--a kind of "if it feels good, do it; fuck the consequences" and YOLO mentality. This is only one kind of hedonism and it is the least sustainable and defensible, which is probably why it is so often used as a strawman to attack hedonism. I cannot imagine this kind of nihilistic hedonism having any practical use.
For hedonists, the pursuit of pleasure in-and-of-itself and the avoidance of pain are absolutely necessary and foundational for understanding ethics and living a truly ethical life (or, the so-called "good life").
Hedonism emphasizes pleasure in-and-of-itself, not pleasure that needs some kind of "function" to make it morally acceptable. For example, Roman Catholicism claims that all sexual acts must be procreative. For a hedonist, on the other hand, a sensual, pleasurable experience can be good in-and-of-itself--no useful "function" necessary.
For hedonists (the practical ones anyway), the "pursuit" of pleasure does not mean the mindless accumulation of more pleasurable experiences, like we are racking up pleasure points.
A practical hedonist's goal would be something like "contentment" (Greek: ataraxia). If one discovers that their pursuit of pleasure is at odds with "contentment," how they are pursuing pleasure should probably be reevaluated and remodeled. But "contentment" is itself a "pleasant" experience that can be classified as "pleasure." So the goal of life is, in fact, the pursuit of pleasure (ataraxia) to which the pursuit of individual pleasurable experiences is essential, not incidental.